In his paper, the author has modelled the behaviour of compression members by assuming that they will have a buckling load given by Rankine's formula, and that they can undergo unlimited contraction at this load. It is well known, however, that compression members generally show some drop of load-carrying capacity after the critical load has been reached. On the other hand, it is quite reasonable to assume that tension members will elongate plastically under a constant yielding load (ignoring strain-hardening effects), provided that premature joint failure is prevented. Results of experimental work on compression members with varying degrees of end restraint have been plotted in Fig Cl. These values were mostly taken from a paper published by Francis and Stevens1 describing work carried out at the University of Melbourne, but also include results from Paris and van den Broek. It can be seen from Fig C1 that the critical loads of compression members are more closely related to the squash and Euler loads than to the Rankine load.